Chapter 11

Question 1

bonding MO

Answer 1

a molecular orbital formed when wave functions are added to each other, which increases electron density between the nuclei. electrons occupying such an orbital stabilize the molecule

Question 2

anti bonding MO

Answer 2

a molecular orbital formed when wave functions are subtracted from each other, which decreases electron density between the nuclei and leaves a node. electrons occupying such an orbital destabilize the molecule

Question 3

homonuclear diatomic molecule

Answer 3

a molecule composed of two identical atoms

Question 4

hybrid orbital

Answer 4

an atomic orbital postulated to form during bonding by the mathematical mixing of specific combinations of nonequivalent orbitals in a given atom

Question 5

hybridization

Answer 5

a postulated process of orbital mixing to form hybrid orbitals

Question 6

MO bond order

Answer 6

one-half the difference between the number of electrons in bonding MOs and the number in antibonding MOs

Question 7

molecular orbital (MO)

Answer 7

an orbital of given energy and shape that extends over a molecule and can be occupied by no more than two paired electrons

Question 8

MO diagram

Answer 8

a depiction of the relative energy and number of electrons in each MO, as well as the atomic orbitals from which the MOs form

Question 9

MO theory

Answer 9

a model that describes a molecule as a collection of nuclei and electrons in which the electrons occupy orbitals that extend over the entire molecule

Question 10

nonbonding MO

Answer 10

a molecular orbital that is not involved in bonding

Question 11

pi bond

Answer 11

a covalent bond formed by sideways overlap of two atomic orbitals that has two regions of electron density, one above and one below the internuclear axis

Question 12

pi MO

Answer 12

a molecular orbital formed by combination of two atomic (usually p) orbitals whose orientations are perpendicular to the internuclear axis

Question 13

sigma bond

Answer 13

a type of covalent bond that arises through end-to-end orbital overlap and has most of its electron density along an imaginary line joining the nuclei

Question 14

sigma MO

Answer 14

a molecular orbital that is cylindrically symmetrical about an imaginary line that runs through the nuclei of the component atoms.

Question 15

sp hybrid orbital

Answer 15

an orbital formed by the mixing of one s and one p orbital of a central atom

Question 16

sp2 hybrid orbital

Answer 16

an orbital formed by the mixing of one s and two p orbitals of a central atom

Question 17

sp3 hybrid orbital

Answer 17

an orbital formed by the mixing of one s and three p orbitals of a central atom

Question 18

sp3d hybrid orbital

Answer 18

an orbital formed by the mixing of one s, three p, and one d orbital of a central atom

Question 19

sp3d2 hybrid orbital

Answer 19

an orbital formed by the mixing of one s, three p, and two d orbitals of a central atom

Question 20

valence bond theory

Answer 20

a model that attempts to reconcile the shapes of molecules with those of atomic orbitals through the concepts of orbital overlap and hybridization